Internal combustion engine control method and internal combustion engine control device

Abstract

In the case of restarting an internal combustion engine that has been automatically stopped during running, the internal combustion engine is restarted by combustion recovery starting when the rotation speed of the internal combustion engine under the input of a restart request is greater than or equal to a predetermined first rotation speed. In the case of restarting the internal combustion engine that has been automatically stopped during running, the internal combustion engine is restarted by cranking recovery starting when the rotation speed of the internal combustion engine under the input of the restart request is lower than the predetermined first rotation speed. The first rotation speed is set lower at the restart of the internal combustion engine in a sailing stop state than at the restart of the internal combustion engine in a coast stop state.

The invention claimed is: 
     
       1. A control method for an internal combustion engine as a driving source of a vehicle, comprising: restarting fuel supply to the internal combustion engine which has been automatically stopped during running of the vehicle,
 wherein, when a rotation speed of the internal combustion engine is lower than a predetermined first rotation speed, cranking of the internal combustion engine is performed at the time of restarting the fuel supply to the internal combustion engine, and 
 wherein the first rotation speed is set lower in a state that a lock-up clutch of a torque converter arranged between the internal combustion engine and a transmission is engaged than in a state that the lock-up clutch of the torque converter is released. 
 
     
     
       2. The control method for the internal combustion engine according to  claim 1 ,
 wherein the first rotation speed is set lower at a first restart in which the fuel supply to the internal combustion engine is restarted from a state that: an accelerator pedal of the vehicle is undepressed; a clutch arranged between the lock-up clutch and driving wheels of the vehicle is released; and the lock-up clutch is engaged, than at a second restart in which the fuel supply to the internal combustion engine is restarted from a state that: a brake pedal of the vehicle is depressed; the clutch is engaged; and the lock-up clutch is released. 
 
     
     
       3. The control method for the internal combustion engine according to  claim 2 ,
 wherein the clutch is released in the first restart. 
 
     
     
       4. A control device for an internal combustion engine,
 the internal combustion engine being provided as a driving source of a vehicle, 
 the vehicle comprising a transmission and a torque converter arranged between the internal combustion engine and the transmission, 
 the control device comprising a control unit that restarts fuel supply to the internal combustion engine which has been automatically stopped upon satisfaction of a predetermined condition during running of the vehicle, 
 wherein, when a rotation speed of the internal combustion engine is lower than a predetermined first rotation speed, the control device performs cranking of the internal combustion engine at the time of restarting the fuel supply to the internal combustion engine, and 
 wherein the first rotation speed is set lower in a state where a lock-up clutch of the torque converter is engaged than in a state where the lock-up clutch of the torque converter is released.